Automatic saws are known in the art. The contribution made by the present invention lies in the improved methods of programming and controlling the work flow and output of these types of saws. Prior to the advent of the present invention, each automatic saw was operated and programmed independently of other automatic saws operating in the same workplace. This situation can often lead to confusion and duplicative efforts because of the lack of communication and coordination amongst the operators of the various saws. Further, the industrial engineer or supervisor in charge of all of the automatic saws had no efficient way to coordinate the efforts of the operators running the saws.
Typically, automatic saws allow an operator to program a first saw job and run that first job while standing at the saw. While the first saw job is running, the operator then has the option to program additional saw jobs into the memory of the programmable controller of the saw. An example of this type of programmable band saw is illustrated in U.S. Pat. No. 4,866,630 which is incorporated herein by reference. The method of sawing disclosed in U.S. Pat. No. 4,866,630 is particularly useful in combination with Marvel Series V10APC, 13APC, 15APC, 25APC and 81APC metal cutting band saw machines. An illustration of these sawing machines is found in Catalog 8104, Marvel Series 81 & 81A band saw machines, and Publication 81-11, Marvel Series 81 & 81A Operator's Manual, both published by Armstrong-Blum Mfg. Co. of Mt. Prospect, Ill., also incorporated herein by reference.
The above combined prior art discloses a sawing machine that has a programmable controller and an automatic workpiece shuttle with a motion encoder. One embodiment includes a blade tilt mechanism with a separate motion encoder. The programmable controller is operably connected to the motion encoders, other sensing means, as well as the working/moving parts of the saw including the shuttle, blade and blade tilt mechanisms.
The programmable controller is capable of storing a series of saw jobs. Each saw job has number of sawing steps. Each step, in turn, defines the sawed workpiece length, and in saw embodiments employing a saw blade tilting mechanism, a sawing angle, both of which may be different from other steps.
The programmable controller receives signals from the motion encoders to determine the shuttle position and, in tiltable embodiments, the blade tilt position, and then uses these positions to control shuttle, tilt and clamp operation. The programmable controller also corrects each workpiece length with a saw kerf and pivot point correction factors, both modified for the sawing angle. In saws that do not have blade tilt mechanisms, the pivot point correction factor is not employed. The programmable controller receives motion increment signals from the motion encoders which are decoded to determine the direction in which the workpiece has traveled.
As stated above, each saw job has one or more sawing steps. Each step defines a machine operation cycle. The data for each step include a pull length, saw angle (in the case of tilt saws) and number of repetitions. A pull length of zero can be specified, in which case no further length of stock will be pulled. The combination of a number of steps in one saw job can result in an intricately shaped product. The sequence of steps can also be repeated a number of times for a simple saw job. Thus, one saw job can generate a quantity of identical workpieces.
Before the development of the present invention, the length, angle and repetition data had to be entered by the operator standing at the saw. With the development of the present invention, the operator can be running a saw job, simultaneously programming additional saw jobs by keyboard at the saw or initiate the downloading of a job from a personal computer and a third person, such as an industrial engineer or supervisor, can be programming additional saw jobs or a range of saw jobs for that same saw at the personal computer. The engineer can also be programming jobs for more than one saw or a series of saws.
The present invention allows a supervisor located away from the saw to control the work flow at the saw. Other saw jobs may be programmed, changed or deleted at the same time that the saw is running a previously programmed saw job, all at a location remote from the saw. The number of repetitions in a job is an additional piece of data which can be entered or changed without the supervisor or engineer travelling down to the shop floor or attempting telephone communication in the very noisy environment in which these saws are used.
By providing additional avenues for saw job programming input, the present invention provides several commercial advantages. First, the present invention allows a more time efficient operation. An engineer, in need of a certain saw job, may simply program that saw job from the personal computer in the office without having to proceed down to the shop floor. Further, the engineer need not orally transmit a saw job to an operator in person or over the phone thereby decreasing the chance of a saw job being incorrectly transmitted or incorrectly performed. It is important to note that these programmable saws are designed to cut hard, expensive and sometimes exotic metals. A saw job incorrectly performed can be very costly to the manufacturer.
The present invention also provides for less saw operator input. Saw operators are now free to run jobs and spend less time programming jobs. While the present invention does not decrease from the ability of an automatic programmable saw to have an operator run and program a job contemporaneously, the present invention places more control in the hands of the engineers and supervisors. Therefore, costly mistakes are less likely to occur. Further, by providing the supervisors and engineers with a means to input saw jobs to a plurality of saws, the work flow of the manufacturing operation may be better controlled. If a manufacturer employs a number of automatic programmable saws, the work flow may be more evenly distributed among the saws thereby increasing output, reducing operator time and reducing saw down time.